Software running on a processor or central processing unit (CPU) to provide functionality in the host device often changes over time. The changes may result from the need to correct bugs, or errors, in the software files, adapt to evolving technologies, or add new features. In particular, embedded software components hosted on mobile wireless devices often include numerous software bugs that require correction.
Software includes one or more files in the form of human-readable American Standard Code for Information Interchange (ASCII) plain text files or binary code. Software files can be divided into smaller units that are often referred to as modules or components. A UNIX platform or personal computer (PC) includes multiple software components, and each of the software components is managed and updated independently through a file system supported by a corresponding operating system (OS). Information used to update software files or software components hosted on UNIX platforms or PCs can be transferred through the Internet or loaded from a secondary storage medium such as a floppy disk, a compact disk read-only memory (CD-ROM), or a compact flash card.
In contrast, in mobile wireless devices, a real-time operating system (RTOS) is typically used in which all software components are linked as a single large file. Further, no file system support is typically provided in these mobile wireless devices. In addition, the single large file needs to be preloaded, or embedded, into the device using a slow communication link like a radio, infrared, or serial link.
Obstacles to updating the large files of mobile wireless devices via slow communication links include the time, bandwidth, and cost associated with delivering the updated file to the device. Distribution of such large files can take an undesirably long time from the point of view of the customer and can consume a large amount of server resources from the point of view of the file provider. Delivering a large file over an unreliable communication link such as a radio link may also increase the rate of communication failure and require a large working memory within the device, for example random access memory (RAM).
One solution to the problem of delivering large files to mobile devices for use in updating files of the mobile devices uses difference programs to generate difference files. The difference files include data that describes how a revised file differs from an original file. While use of the various difference programs helps reduce the size of the transferred files, network traffic management issues remain because the service provider or software provider has many subscribers or customers to which they must potentially provide updated files including difference files.
Generally, the number of subscribers supported by a service provider along with bandwidth limitations of the associated network prohibits timely updates of all files on all subscriber devices each time a new update becomes available. However, the service provider does have to ensure that particular updates (e.g., bug fixes) to particular files are distributed in a timely fashion. Therefore, even when using difference files to reduce the network bandwidth requirements per file transfer, the service provider is faced with managing the delivery of software upgrades to large numbers of supported users.
In the drawings, the same reference numbers identify identical or substantially similar elements or acts. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the Figure number in which that element is first introduced (e.g., element 116 is first introduced and discussed with respect to FIG. 1).
Unless described otherwise below, the construction and operation of the various blocks and structures shown in the Figures are of conventional design. As a result, such blocks need not be described in further detail herein, because they will be understood by those skilled in the relevant art. Such further detail is omitted for brevity and so as not to obscure the detailed description of the invention. Any modifications necessary to the Figures can be readily made by one skilled in the relevant art based on the detailed description provided herein.